Hepatitis A Vaccine
Content reviewed against published CDC, AAP, WHO guidelines
Last reviewed:
Key takeaways
- Prevents: Hepatitis A virus infection, Acute liver inflammation
- Schedule: 2 doses starting at 12 months
- Effectiveness: The hepatitis A vaccine is 94-100% effective after the full 2-dose series.
- Most common side effect: Soreness, redness, or swelling at injection site
How it works
The hepatitis A vaccine contains inactivated (killed) hepatitis A virus. The virus is grown in human cell cultures, purified, and then inactivated with formalin so it cannot cause disease. When injected, the immune system recognizes the viral proteins and produces antibodies that provide long-lasting protection against future hepatitis A infection.
Recommended schedule
| Dose | Age |
|---|---|
| Dose 1 | 12 months |
| Dose 2 | 18 months (at least 6 months after dose 1) |
Side effects
Common (mild, resolve in 1-2 days)
- Soreness, redness, or swelling at injection site (20-50%)
- Loss of appetite
- Fussiness or irritability
- Mild headache
- Low-grade fever
- Fatigue or drowsiness
Serious (very rare)
- Severe allergic reaction (anaphylaxis) — extremely rare, fewer than 1 per million doses
- No confirmed serious adverse events causally linked to the hepatitis A vaccine in large post-marketing surveillance studies
Who should NOT get this vaccine
- Severe allergic reaction (anaphylaxis) to a previous dose of hepatitis A vaccine
- Known severe allergy to any vaccine component (including neomycin or alum)
- Children younger than 12 months of age (not approved for this age group in routine use)
- Moderate or severe acute illness (defer vaccination until recovery)
Effectiveness
The hepatitis A vaccine is 94-100% effective after the full 2-dose series. Even a single dose provides 95% protection within 2-4 weeks. The 2-dose series provides protection lasting at least 25 years and likely lifelong.
Available brands
Havrix
GlaxoSmithKline
Vaqta
Merck
Myths vs. facts
Myth: “Hepatitis A only affects people in developing countries”
Fact: Hepatitis A outbreaks regularly occur in the United States. Between 2016-2022, the US experienced widespread outbreaks with over 44,000 cases, 27,000 hospitalizations, and more than 400 deaths. Children can be exposed through contaminated food, travel, or community spread.
Myth: “My child doesn't need this vaccine because hepatitis A isn't serious in children”
Fact: While hepatitis A is often milder in young children (many are asymptomatic), infected children can spread the virus to adults and older family members who may become seriously ill. Vaccination protects the child and the community.
Myth: “Good hygiene alone is enough to prevent hepatitis A”
Fact: While handwashing helps, hepatitis A is highly contagious and can spread before symptoms appear. The virus can survive on surfaces for months and is resistant to many common disinfectants. Vaccination is the most reliable protection.
Frequently asked questions
Why isn't hepatitis A vaccine given before 12 months?
What if my child misses the second dose?
Can hepatitis A vaccine be given with other vaccines?
Is my child protected after just one dose?
Sources
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Bottom line
The Hepatitis A Vaccine (HepA) is safe, well-studied, and recommended by the CDC, AAP, and WHO. Talk to your pediatrician if you have questions about timing or your child's specific health needs.
Choosing to vaccinate your child is one of the most important things you can do to protect their health. If you have concerns, your pediatrician is always happy to talk through them with you.